Line-contact dry electrode

ABSTRACT

A line-contact dry electrode comprises a conductive electrode base and at least one conductive contact member extending from the conductive electrode base. The conductive contact member includes a plurality of elastic conductive branches arranged intermittently to form a comb-like electrode able to comb and push away the testee&#39;s hair and contact the testee&#39;s skin.

RELATED APPLICATIONS

This application is a Divisional patent application of co-pendingapplication Ser. No. 13/917,852, filed on 14 Jun. 2013, now pending. Theentire disclosure of the prior application, Ser. No. 13/917,852 isconsidered a part of the disclosure of the accompanying Divisionalapplication and is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a line-contact dry electrode,particularly to a comb-like line-contact dry electrode.

2. Description of the Related Art

In recent years, electro-biomedical signal measurement devices, whichcan detect physiological signals from skin, have been extensively usedin medical diagnosis and research, including electrocardiography (ECG),electroencephalography (EEG), electromyography (EMG), galvanic skinreflex (GSR), and body fat meters. The electro-biomedical signalmeasurement devices are non-invasive detectors. For an example, EEG canrecord brainwaves and features economy, safety, easy operation, andcomfortable inspection environment. Therefore, EEG has been widely usedin clinic diagnosis and neurobiological research, such as inspectionsfor patients of coma, apoplexy, epilepsy, encephalitis, Parkinson'sdisease, and other brain diseases.

The sensor electrodes used by EEG may be categorized into the wetelectrodes and the dry electrodes. While the wet electrode is used, thetestee's skin normally needs processing beforehand, such as removing thehorny layer or shaving the hair-rich region, so as to overcome too highinterface impedance between the skin and the electrode. Further,conductive paste is applied to the testee's skin to achieve bettermeasurement quality. With time elapsed, the conductive paste will dry,and its conductivity will decay. Therefore, the conductive paste needsapplying to the testee's skin repeatedly, which not only may irritatethe testee's skin but also makes the operation complicated andtime-consuming. The dry electrode is fabricated with amicroelectromechanical technology and less likely to damage inmeasurement. The dry electrode normally uses a flat probe module tocontact the testee's skin and detect the physiological signals withoutusing any conductive paste. The dry electrode can directly contact theskin of a hair-rich region, e.g. the head skin. The dry electrodeoutperforms the wet electrode in some respects. However, the flat probemodule is unlikely to comply with the contour of the head. Further, hairis likely to interfere with measurement and affect the precisionthereof. Thus, the dry electrode can not effectively work in EEG, whichis undertaken on the head. Therefore, how to decrease the discomfort thedry electrode causes to testees and increase the precision ofmeasurement using the dry electrode is a problem the field concerned iseager to overcome.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide aline-contact dry electrode, which is an elastic comb-like electrode ableto comb and push away the testee's hair and closely contact the headskin, whereby is promoted precision of physiological signal measurement.

A further objective of the present invention is to provide aline-contact dry electrode, which is simple-structured and bendable, andwhich applies to soft EEG caps and hard EEG caps, whereby is promotedthe application flexibility thereof.

To achieve the abovementioned objectives, the present invention proposesa line-contact dry electrode, which comprises a conductive electrodebase and at least one conductive contact member, wherein the conductivecontact member has a plurality of elastic conductive branches arrangedintermittently to form a comb-like electrode able to comb and push awaythe testee's hair and contact the head skin. The elastic conductivebranches can comply with the contour of the head and closely contactsthe head skin. Thereby, physiological signals can be measured moreaccurately.

Each individual electrode of the present invention corresponds to asingle signal channel. The branches of an electrode of the presentinvention can be respectively adjusted to contact the testee's skinclosely, whereby the testee can wear the electrode comfortably during along interval of test, and whereby is lowered interference onmeasurement.

Below, embodiments are described in detail to make easily understood theobjectives, technical contents, characteristics and accomplishments ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a line-contact dry electrode according to afirst embodiment of the present invention;

FIG. 2 schematically shows an application of a line-contact dryelectrode to an EEG cap according to one embodiment of the presentinvention;

FIG. 3 schematically shows a line-contact dry electrode according to asecond embodiment of the present invention;

FIG. 4 schematically shows a line-contact dry electrode according to athird embodiment of the present invention; and

FIG. 5 schematically shows a line-contact dry electrode according to afourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In order to realize precision, comfortable and painless EEG measurement,the present invention proposes a novel line-contact dry electrode, whichis applicable to soft EEG caps and hard EEG caps and will be veryhelpful to medical inspection.

Refer to FIG. 1 for a first embodiment of the present invention. Theline-contact dry electrode of the present invention comprises aconductive electrode base 10 and at least one conductive contact member12 extending from the conductive electrode base 10. The conductivecontact member 12 includes a plurality of elastic conductive branches 14arranged intermittently to form a comb-like electrode able to comb andpush away the testee's hair and contact the testee's skin. Theconductive electrode base 10 and the conductive contact member 12 arefabricated into a one-piece component. The conductive electrode base 10and the conductive contact member 12 are preferably made of a metallicmaterial. In the first embodiment, the conductive electrode base 10 isfabricated into a plane structure. The elastic conductive branches 14 ofthe conductive contact member 12 are extended from one lateral of theconductive electrode base 10, arranged intermittently, and bended atdifferent positions successively to run downward and then horizontally.In FIG. 1, each elastic conductive branch 14 is bended from one lateralof the conductive electrode base 10 by 180 degrees to form a firstcamber 141. Next, the elastic conductive branch 14 is extended parallelto the conductive electrode base 10 for a distance of L1 to form a firstextension 142. Next, the elastic conductive branch 14 is bended downwardby 90 degrees to form a second camber 143 and then extended for adistance of H to form a second extension 144. Next, the elasticconductive branch 14 is bended upward by 90 degrees to form a thirdcamber 145 and then extended parallel to the first extension 142 in thesame extending direction of the first extension 142 for a distance of L2to form a third extension 146. Next, the elastic conductive branch 14 isbended by 180 degrees to form a fourth camber 147 and then extendedparallel to the third extension 146 but opposite to the extendingdirection of the third extension 146 for a distance of L3 to form afourth extension 148, which is parallel to the conductive electrode base10. The terminal of each elastic conductive branch 14 is bended upwardto have a curve corresponding to the first bended region (such as thefirst camber 141).

The reasons why the elastic conductive branches 14 are bended in theabovementioned way are that the elastic fourth extensions 148 can comband push away the testee's hair, flexibly adapt to the contour of thehead skin, and closely contact the head skin and that the curves of theterminals of the elastic conductive branches 14 can prop again the headskin smooth and easily without pain. Thus is overcome the problem thatthe terminals of the conventional electrodes are likely to prick andhurt the head skin of testees. The hair combed and pushed by the elasticconductive branches 14 along the spacings between the elastic conductivebranches 14 will be accommodated in the spaces formed by the conductiveelectrode base 10, the first extensions 142, the second extensions 144and the third extension 146 without entanglement. In one embodiment, theadaptability of the dry electrode is increased via modifying thestructure of the dry electrode. For example, each elastic conductivebranch 14 is perforated to have a hole 16, whereby is decreased thecompression on the elastic conductive branches 14, increased the overalltoughness of the dry electrode, and prolonged the service life of thedry electrode. The present invention does not constrain that theconductive contact member 12 must be bended in the abovementioned way.All the dry electrodes whose conductive contact member is bended atdifferent positions successively to form a comb-like electrode adaptableto various contours of the head are to be included within the scope ofthe present invention.

Refer to FIG. 1 and FIG. 2. FIG. 2 schematically shows the applicationof a line-contact dry electrode to an EEG cap according to oneembodiment of the present invention. The operator (such as medicalpersonnel) may arranges several line-contact dry electrodes in an EEGcap 18 (such a soft EEG cap) according to requirement. The EEG cap 18has a plurality of through-holes 182. The conductive electrode base 10has a first fixing element 20 (such as a male fastener). A portion ofthe first fixing element 20 is inserted through the through-hole 182 ofthe EEG cap 18 for fixing the conductive electrode base 10 on the innersurface of the EEG cap 18. A second fixing element 22 (such as a femalefastener) corresponding to the first fixing element 20 is press-fittedwith the first fixing element 20 from the outer surface of the EEG cap18. The first fixing element 20 and the second fixing element 22 aremade of a conductive material (such as a metallic material). A signalcable 24 is connected with the second fixing element 22. After thesecond fixing element 22 is press-fitted with the first fixing element20, the signal cable 24 is electrically connected with the dryelectrode. In measurement, the testee wears the EEG cap 18. Whilecompressed, the conductive electrode base 10 actuates the elasticconductive branches 14 to comply with the contour of the testee's head,push away the testee's hair, and closely contact the head skin. As longas sufficient area of the head skin is contacted by the line-contact dryelectrode, the operator begins to measure the physiological signals ofthe testee. The physiological signals are transmitted to an externaldevice (such as a brainwave detector) via the signal cable 24.

Refer to FIG. 3 for a second embodiment. In addition to theabovementioned line-contact dry electrode with a successively-bendedstructure, the present invention also proposes a line-contact dryelectrode with a different structure in the second embodiment. In thesecond embodiment, the conductive electrode base 10 is a circular-shapedplane. The elastic conductive branches of the conductive contact member12 radiate from the circumference of the conductive electrode base 10and extend downward vertically. Each elastic conductive branch is bendedto form an L-shaped conductive contact member 26. The terminal of eachL-shaped conductive contact member 26 is bended upward to have a curve.The L-shaped conductive contact member 26 has flexibility. Whilecompressed, the flexible L-shaped conductive contact member 26 comb andpush away the testee's hair radially, complying with the contour of thetestee's head. The design of curving the terminal of the L-shapedconductive contact member 26 provides testees with comfortable andpainless measurement. In one embodiment, a bended region 262 of eachL-shaped conductive contact member 26 is perforated to have a hole 16 toincrease the toughness of the elastic conductive branches and avoid thedistortion of the elastic conductive branches.

Refer to FIG. 4 for a third embodiment. In the third embodiment, theconductive electrode base 10 is a plane structure, and there are twoconductive contact members. The two conductive contact members areextended from the same face of the conductive electrode base 10 andbended downward vertically to respectively form a first L-shapeconductive contact member 28 and a second L-shape conductive contactmember 30. The L-shape conductive contact member 28 has a plurality offirst elastic conductive branches 282. The second L-shape conductivecontact member 30 has a plurality of second elastic conductive branches302. The first L-shape conductive contact member 28 and the secondL-shape conductive contact member 30 are symmetrically bended towardopposite directions. Each of the terminals of the first elasticconductive branches 282 and the second elastic conductive branches 302is bended upward to have a curve, which makes the conductive branchesslide smooth on the head skin and decreases the force applied on thehead skin. While compressed, the first elastic conductive branches 282and the second elastic conductive branches 302 respectively comb andpush away the testee's hair toward opposite directions and contact thehead skin, complying with the contour of the testee's head. In oneembodiment, each of the bended regions of the first elastic conductivebranches 282 and the second elastic conductive branches 302 isperforated to have a hole 16.

Refer to FIG. 5 for a fourth embodiment. In the fourth embodiment, theconductive electrode base 10 is an arch structure, and there are twoconductive contact members. The two conductive contact members arebended symmetrically to respectively form a first arch-shaped conductivecontact member 32 and a second arch-shaped conductive contact member 34,which are pivotally coupled by a shaft 36. The first arch-shapedconductive contact member 32 has a plurality of first arch-shapedelastic conductive branches 322. The second arch-shaped conductivecontact member 34 has a plurality of second arch-shaped elasticconductive branches 342. The first arch-shaped elastic conductivebranches 322 are staggered from the second arch-shaped elasticconductive branches 342. While the conductive electrode base 10 iscompressed, the first arch-shaped elastic conductive branches 322 andthe second arch-shaped elastic conductive branches 342 are pivotallymoved toward each other to contact each other in a staggering way, orpivotally moved far away from each other in a staggering way, with theshaft 36 being the pivotal axis. Thus, the first arch-shaped elasticconductive branches 322 and the second arch-shaped elastic conductivebranches 342 comb and push away the testee's hair in opposite directionsto contact at least two regions of the head skin. The present inventiondoes not limit the application of the fourth embodiment. In fact, thestructure of the fourth embodiment is applicable to hard EEG caps andsoft EEG caps. Each of the terminals of the first arch-shaped elasticconductive branches 322 and the second arch-shaped elastic conductivebranches 342 is bended upward to form a curve, which makes theconductive branches slide smooth on the head skin and decreases theforce applied on the head skin.

In the second, third and fourth embodiments, the conductive electrodebase may have a first fixing element, which can be press-fitted with asecond fixing element to facilitate measurement. The installation methodof the first fixing element is similar to that described in the firstembodiment and will not repeat herein. The present invention is a singledry electrode corresponding to a single channel. The single dryelectrode of the present invention has a plurality of branches, whichdeform independently under compression. In addition to being perforatedto have a hole, the structure of the elastic conductive branch can alsobe modified via notching, which will reduce the width of the elasticconductive branch and make the elastic conductive branches deform andcomply with the contour of the testee's head more easily. Alternatively,a thinned region is formed on each elastic conductive branch and has asmaller thickness than the conductive electrode base and the other partof the elastic conductive branch. As the thinned region is more likelyto deform under compression, it increases the adaptability of the dryelectrode and makes the elastic conductive branches contact the testee'sskin (such as the head skin) more compliantly. Therefore, the presentinvention can make the testee comfortably wear the EEG cap for a longtime and reduce noise in measurement. However, the present inventiondoes not constrain the method of modifying the structure of the elasticconductive branches. Any design that can increase the compliance andadaptability of the elastic conductive branches is to be included withinthe scope of the present invention.

In conclusion, the present invention proposes a line-contact dryelectrode, which is simple-structured and made of an elastic materialhaving flexibility and memorability, and which is fabricated into aone-piece component, wherein the elastic comb-like electrode combs andpushes away the testee's hair to contact the testee's skin closely,whereby is promoted precision of physiological signal measurement. Thepresent invention is applicable to soft EEG caps and hard EEG caps andadaptable in application.

The embodiments described above are only to exemplify the presentinvention but not to limit the scope of the present invention. Anyequivalent modification or variation according to the spirit of thepresent invention is to be also included within the scope of the presentinvention, which is based on the claims stated below.

What is claimed is:
 1. A line-contact dry electrode comprising aconductive electrode base and at least one conductive contact memberextending from said conductive electrode base, wherein said conductivecontact member includes a plurality of elastic conductive branchesarranged intermittently to form a comb-like electrode able to comb andpush away testee's hair and contact testee's skin.
 2. The line-contactdry electrode according to claim 1, wherein said conductive electrodebase has a first fixing element press-fitted with a second fixingelement installed on a cap.
 3. The line-contact dry electrode accordingto claim 2, wherein said first fixing element is a male fastener, andsaid second fixing element is a female fastener, and wherein said malefastener is press-fitted with said female fastener.
 4. The line-contactdry electrode according to claim 1, wherein said elastic conductivebranches of said conductive contact member are extended down from onelateral of said conductive electrode base and bended at differentpositions successively to run downward and then horizontally with thelast sections parallel to said conductive electrode base.
 5. Theline-contact dry electrode according to claim 4, wherein said conductiveelectrode base has a first fixing element press-fitted with a secondfixing element installed on a cap.
 6. The line-contact dry electrodeaccording to claim 5, wherein said first fixing element is a malefastener, and said second fixing element is a female fastener, andwherein said male fastener is press-fitted with said female fastener. 7.The line-contact dry electrode according to claim 1, wherein a terminalof each said elastic conductive branch is bended upward to form a curve.8. The line-contact dry electrode according to claim 1, wherein eachsaid elastic conductive branch has a hole or a notch.
 9. Theline-contact dry electrode according to claim 1, wherein each saidelastic conductive branch has a thinned region with a thickness smallerthan that of said conductive electrode base and that of the otherportion of said elastic conductive branch.